Implant syringe

ABSTRACT

An implant syringe with a syringe needle holder, having an axially adjoining preparation receptacle; an outer sleeve with a radially projecting front gripping section, connected together for common axial movement; an inner sleeve, on which the outer sleeve is slidably located and in which the syringe needle is movable with the preparation receptacle. The inner sleeve has axial slots, through which webs engage, which connect the outer sleeve to the syringe needle holder, further including a rod-shaped piston, fastened to a rear gripping section partially surrounded by a rear sleeve, movably engaged in the inner sleeve. The rod-shaped piston is advanceable through the preparation receptacle in the syringe needle so that a distance remains between the tip of the syringe needle and the head end of the piston approximately equal to the length of the preparation to be delivered.

PRIORITY CLAIM

This application claims priority under 35 U.S.C. §§ 119 and 365 toGerman Application No. 10 2017 007893.9, filed Aug. 19, 2017

BACKGROUND OF THE INVENTION

The invention relates to an implant syringe, which is used to deliver athread-like preparation with a long-term active substance into the bodyof a patient. The long-term preparation is generally positioned in theabdominal wall of a patient, into which a receiving passage for thepreparation was previously pierced by means of a syringe needle.

DE 19734385 C1 discloses an implant syringe, which includes a syringeneedle arrangement consisting of a syringe needle, a projecting grippingmember and a preparation receptacle, which are connected together andare situated in a guide device for common axial movement. The implantsyringe further has a piston, whose advance in the direction of thesyringe needle is limited by an abutment so that a distance remainsbetween the tip of the injection needle and the head end of the piston,which is at least equal to the length of a preparation to be delivered,whereby the syringe needle arrangement is retractable by means of thegripping member by at least a distance equal to the length of thepreparation. This implant syringe is operated so that firstly theinsertion passage is formed by the syringe needle being pierced, forinstance into the abdominal wall of a patient until the front edge of aguide sleeve of the implant syringe rests on the skin of the patient.The piston is then advanced by engaging behind a base plate of a spaceron the implant syringe and exerting pressure on an end plate connectedto the piston. The piston pushes the preparation forward into thesyringe needle until a sleeve connected to the piston impinges againstthe base plate of the spacer. The implant syringe is then gripped at thefront gripping member and the base plate of the spacer, whereafter thegripping member is retracted to an abutment. On impingement against theabutment, the syringe needle is completely retracted from thepreparation, which is thus delivered into the insertion passage,whereafter the implant syringe is removed. A preparation may bedelivered gently into the insertion passage with such an implantsyringe. The disadvantage of this known implant syringe resides in thefact that in order to retract the syringe needle it is necessary toengage around it, whereby the manipulation of the syringe is rendereddifficult.

DE 19961197 B4 discloses an implant syringe in which this disadvantageis avoided. In this implant syringe, the gripping position need not bealtered. The advance of the piston is followed directly by theretraction of the syringe needle so that its handling is facilitated andrequires a lesser period of time. Disadvantages of this implant syringeare seen in the fact that the gripping member, with which the syringeneedle arrangement is retracted, is arranged on the front end region ofthe implant syringe so that when operating the implant syringe thefingers of the hand of the doctor must be spread widely and that afterretracting the syringe needle there is the risk of injuring oneself onthe syringe needle due to the slotted guide sleeve. Since furthermorethe preparation is advanced by the piston through a constriction in thepassage, the preparation can be abraded or even break.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide an implant syringein which at least one of the above disadvantages is avoided.

The object is solved in accordance by providing an implant syringecomprising a syringe needle holder, which holds an injection needle, anaxially adjoining preparation receptacle and an outer sleeve with aradially projecting front gripping section on its rear end section. Theinjection needle holder and the outer sleeve are connected together forcommon axial movement, including an inner sleeve, on which the outersleeve is slidably located and in which the syringe needle is movablewith the preparation receptacle, The inner sleeve has axial slots,through which webs extend, which connect the outer sleeve to the syringeneedle holder. The syringe further comprises a rod-shaped piston, whichis fastened to a rear gripping section and is partially surrounded by arear sleeve, which movably engages in the inner sleeve. The rod-shapedpiston is advanceable through the preparation receptacle into thesyringe needle so far that a spacing remains between the tip of thesyringe needle and the head end of the piston, which is approximatelyequal to the length of the preparation to be delivered. The advance ofthe piston is limited by the rear gripping section reaching the rearedge of the inner sleeve. The outer sleeve is releasably locked in theadvanced starting position with the syringe needle exposed by a blockingdevice, which is arranged on the inner sleeve and projects radiallyoutwards. The blocking device is moved radially inwards on advance ofthe rear sleeve into its end position, whereby the outer sleeve isreleased and is retractable by means of the front gripping section onthe inner sleeve.

Advantageous embodiments of the invention are described herein below.

The implant syringe in accordance with the invention has a syringeneedle holder, to which a syringe needle is fastened, adjoining whichthere is a preparation receptacle, the passage of which merges into thepassage of the syringe needle. The syringe needle holder is connected toan outer sleeve of the implant syringe, which has a projecting grippingsection at its rear end, which is referred to as the front grippingsection, whereby the syringe needle, the syringe needle holder and thepreparation receptacle are connected to the outer sleeve for commonaxial movement together.

The outer sleeve is located slidably on an inner sleeve, whereby theouter sleeve is non-rotatably arranged with respect to the inner sleeve.In an intermediate region, the inner sleeve has a plurality of slots,which are spaced from one another in the peripheral direction andthrough which webs engage, which connect the outer sleeve to the syringeneedle holder. The slots extend preferably over a length which is thesame as the range of movement of the syringe needle holder.

The implant syringe in accordance with the invention further includes arod-shaped piston, which is fastened to a preferably circular plate,which serves as a rear gripping section on actuation of the implantsyringe. The piston is surrounded over a rear portion of its length by asleeve, which engages slidably and non-rotatably in the inner sleeve.The piston may be advanced so far through the preparation receptacleinto the syringe needle that a spacing remains between the tip of thesyringe needle and the head end of the piston, which is approximatelyequal to the length of the of the preparation to be delivered or issomewhat larger. The advance of the piston is limited by the reargripping section reaching the rear edge of the inner sleeve. Until thisoccurs, the outer sleeve is locked in its advanced starting position, inwhich the syringe needle is exposed, by a blocking device so that theouter sleeve cannot be retracted with the syringe needle. The blockingdevice is preferably formed on the inner sleeve and projects radiallybeyond it outwardly so that it blocks the retraction of the outersleeve. In this position, it can engage, for instance, a rear shoulderon the outer sleeve. When the rear sleeve is advanced into its endposition, the blocking device is pulled radially inwardly so that thepath of movement of the outer sleeve is free and it can be retractedtogether with the syringe needle by means of the front gripping member.

In this construction, the distance between the two gripping members,which are gripped to operate the implant syringe, is considerablyreduced since the front gripping member is situated at the end of theelongate outer sleeve. The operation of the implant syringe is herebymade considerably easier, particularly for those people who have smallhands.

It is proposed with great advantage that the blocking device is a springarm cut free from the inner sleeve, the locking hook of which projectsradially beyond the inner sleeve in the condition in which it isunloaded by the rear sleeve and blocks the retraction of the outersleeve. The rear sleeve can have an axial slot, into which the springarm slides, seen relatively, wherein at least one oblique surfaceimpinges against a lateral formation on the spring arm or impingesdirectly on the spring arm, which pulls the spring arm radially inwardsand thus removes the locking hook from the path of movement of the outersleeve.

This process is complete when the rear sleeve has reached its front endposition, in which the rear gripping section abuts against the rear edgeof the inner sleeve.

The retraction of the outer sleeve is preferably terminated when the twogripping sections engage one another. It is preferred that when theouter sleeve is completely retracted the piston projects beyond the tipof the syringe needle.

In a further advantageous embodiment of the invention, a spring armprojects into the passage in the preparation receptacle, which rests onthe preparation and fixes it in position or constricts the passage inthe unloaded state so that movement of the preparation is blocked sothat the preparation cannot discharge out of the implant syringe whenthis is not desired. It is advantageously provided that the spring armprojects flatly into the passage, preferably flatly convexly curved.When the piston advances the preparation through this constriction, thespring arm is pressed outwardly, whereby this process occurs so gentlythat the preparation is not abraded or cannot break. It is also proposedwith advantage that the inner sleeve has a head section adjoining theslotted region, which is closed over its periphery and which covers thetip of the syringe needle in its retracted end position. The headsection has a frustoconical shape which preferably tapers forwardly. Itis thus ensured that even when the implant syringe removed from thepatient is handled in an unskilled manner there is no risk of injury bythe tip of the syringe needle.

Further details of the invention will be apparent from the followingdescription of a preferred embodiment of the implant syringe and withreference to the drawings, in which, to different scales.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a to 1c are different views of an embodiment of the implantsyringe;

FIGS. 2a to 2d are different views of the rear sleeve with therod-shaped piston;

FIGS. 3a to 3d show further details of the rear sleeve;

FIG. 4 is a view of the inner sleeve composed of two parts;

FIGS. 5a to 5d are different views of the front portion of the innersleeve;

FIGS. 6a to 6d are different views of the rear portion of the innersleeve;

FIG. 7 is a longitudinal sectional view of the outer sleeve;

FIGS. 8a to 8d are different views of the preparation receptacle;

FIG. 9 shows the blocking device of the outer sleeve.

DETAILED DESCRIPTION

FIGS. 1a to 1c show an initial state of the implant syringe, in whichthe syringe needle 1 is covered by a removable protective cap 2. Theremovable protective cap 2 is readily removably snap connected to anouter sleeve 3. The outer sleeve 3 has an elongate cylindrical shape,wherein a radially projecting front gripping section 4 is integrallyformed at its end section on the right in the figures. The outer sleeve3 is firmly connected by means of a plurality of radially inwardlyextending webs 5 to a needle holder 6, in which the syringe needle 1 isfastened. A preparation receptacle 7 is so arranged axially behind theneedle holder 6 that its passage 8 is in alignment with the passage ofthe syringe needle 1. Situated in this preparation receptacle 8 there isa preparation, which is not shown, which, when the implant syringe isused, is delivered e.g. into the abdominal wall of a patient.

The outer sleeve 3 sits (when it is not blocked) movably on an innersleeve 9, which is composed of a front portion 10 and a rear portion 11.The front portion 10 includes a front section 12, which narrowsfrustoconically and which is closed in the peripheral direction andcovers the tip of the completely retracted syringe needle. The axiallyadjoining region includes webs 13, which are spaced in the peripheraldirection and are provided with slits 14, whereby formed on the endsections of two webs there are hooks 15, which latch into openings 16 inthe rear portion 11 of the inner sleeve 9 in order to connect the twoportions.

The rear portion 11 of the inner sleeve 9 includes a spring arm 17,which is cut free from the wall of the inner sleeve portion 11 andprojects radially outwardly with a locking hook 25. This spring arm 17with the locking hook 25 serves as a blocking device for the outersleeve 3 so long as a rear sleeve 18 is not slid into its end positionin the rear portion 11 of the inner sleeve 9.

Integrally formed at the rear end of the rear sleeve 18 there is a flatgripping member 19, secured centrally to which in the sleeve 18 there isa rod-shaped piston 20. The rear sleeve 18 includes a slot 21 extendingin the axial direction, which, when the rear sleeve 18 is slid into therear portion 11 of the inner sleeve 9, so cooperates with the spring arm17 by means of an oblique surface 26 that its locking hook 25 is drawnradially inwards. This is the case when the inner surface of the reargripping member 19 abuts the rear edge 22 of the inner sleeve 9, wherebythis position is readily releasably locked.

The outer sleeve 3 can now be retracted together with the injectionneedle 1 in its end position, in which the two gripping members 4 and 19engage one another. The tip of the injection needle 1 is now situatedwithin the frustoconical section 12 of the inner sleeve 9.

FIG. 1a shows a safety sleeve 22, which, in the initial state of theimplant syringe, blocks the advance of the rear sleeve 18 and thus ofthe piston 12 with webs. The safety sleeve 22 is removed before use ofthe implant syringe.

FIGS. 8a to 8d show the preparation receptacle 7, which is arrangedbehind the syringe needle holder. Projecting into the through passage 23of the preparation receptacle 7 there is a spring arm 24, which is cutfree from the peripheral wall of the preparation receptacle 7 and which,in the unloaded state, so constricts the through passage 23 that apreparation received therein cannot pass the spring arm 24. The springarm has a gently convex shape projecting into the passage 23 and isconstructed integrally with the remainder of the preparation receptacle7. When the piston 20 is advanced, it presses the preparation smoothlythrough the constriction, whereby the spring arm is pressed somewhatupwardly. The preparation can thus not be damaged.

FIG. 9 is an enlarged schematic view of the blocking device for theouter sleeve 3. The inner sleeve 9 engages a rear annular shoulder 27 ofthe outer sleeve in this view with a radially outwardly projectinglocking hook 25. When the rear sleeve 18 is advanced in the direction ofthe arrow 28, an oblique surface 26 on the rear sleeve 18 slides along arelease ramp 29 on the inner sleeve 9, whereby the locking hook 25 ispulled radially inwardly and permits the outer sleeve 3 to be pulledback.

1. An implant syringe comprises a syringe needle holder, which holds aninjection needle, an axially adjoining preparation receptacle and anouter sleeve with a radially projecting front gripping section on itsrear end section, wherein the injection needle holder and the outersleeve are connected together for common axial movement, including aninner sleeve, on which the outer sleeve is slidably located and in whichthe syringe needle is movable with the preparation receptacle, whereinthe inner sleeve has axial slots, through which webs extend, whichconnect the outer sleeve to the syringe needle holder, further includinga rod-shaped piston, which is fastened to a rear gripping section and ispartially surrounded by a rear sleeve, which movably engages in theinner sleeve, wherein the rod-shaped piston is advanceable through thepreparation receptacle into the syringe needle so far that a spacingremains between the tip of the syringe needle and the head end of thepiston, which is approximately equal to the length of the preparation tobe delivered, and the advance of the piston is limited by the reargripping section reaching the rear edge of the inner sleeve, wherein theouter sleeve is releasably locked in the advanced starting position withthe syringe needle exposed by a blocking device, which is arranged onthe inner sleeve and projects radially outwards, and wherein theblocking device is moved radially inwards on advance of the rear sleeveinto its end position, whereby the outer sleeve is released and isretractable by means of the front gripping section on the inner sleeve.2. An implant syringe as claimed in claim 1, wherein the blocking deviceis a spring arm cut free from the inner sleeve, the head end of which,which is preferably shaped in the form of a locking hook, projectsradially beyond the inner sleeve in the unloaded state and blocks theretraction of the outer sleeve.
 3. An implant syringe as claimed inclaim 1, wherein the rear sleeve has an axial slot, which slides overthe spring arm, which is thus drawn radially inwardly by at least oneoblique surface.
 4. An implant syringe as claimed in claim 1, whereinthe front end position of the rear sleeve is reached when the reargripping section abuts the rear edge of the inner sleeve.
 5. An implantsyringe as claimed in claim 1, wherein the retraction of the outersleeve is limited by the two gripping sections engaging one another. 6.An implant syringe as claimed in claim 1, wherein when the outer sleeveis completely retracted, the piston projects beyond the tip of thesyringe needle.
 7. An implant syringe as claimed in claim 1, whereinprojecting into the passage of the preparation receptacle there is aspring arm which, in the unloaded state, blocks the movement of thepreparation.
 8. An implant syringe as claimed in claim 7, wherein thespring arm projects in a flatly convex curved manner into the passage.9. An implant syringe as claimed in claim 1, wherein the inner sleeveincludes a head section, which adjoins the slotted region and is closedover the periphery and which covers the tip of the syringe needle in itsretracted end position.
 10. An implant syringe as claimed in claim 9,wherein the head section has a forwardly tapering frustoconical shape.